Acid-catalysed carboxymethylation, methylation and dehydration of alcohols and phenols with dimethyl carbonate under mild conditions

Abstract

Dimethyl carbonate (DMC) chemistry has been extended to include acid-catalysed reactions of different aliphatic alcohols and phenols.

Environmentally-Benign Dimethyl Carbonate-Mediated Production of Chemicals and Biofuels from Renewable Bio-Oil

“…The chemical catalysis is faster than the enzymatic process. Among the different kinds of chemical catalysis, alkaline catalysis has been widely employed in DMC-mediated biofuels and chemicals production [34,41,66,69,78]. The cost of alkaline catalysts, such as metal hydroxides, alkoxides and metal oxides, is comparatively cheaper than enzyme, and high yields have been obtained with chemical catalysis [59].…”

“…Brønsted and Lewis acids were used in DMC-mediated carboxymethylation and methylation with various alcohols and phenols [66]. Deshmukh et al [67] reported that the use of Brønsted and Lewis acidic ionic liquids enhanced the yield of diphenyl carbonate (DPC) synthesis.…”

“…Deshmukh et al [67] reported that the use of Brønsted and Lewis acidic ionic liquids enhanced the yield of diphenyl carbonate (DPC) synthesis. DPC, one of the most important intermediates for producing various organic and polymeric materials, was produced by a two-step process involving transesterification and the disproportionation reactions [17,66]. The synthesis of five-and six-membered heterocycles from 1,4-, 1,5-diols or 1,4-aminoalcohols with DMC has been developed with a nitrogen bicyclic base.…”

Lewis acidic FeCl3promoted 2-aza-Cope rearrangement to afford α-substituted homoallylamines in dimethyl carbonate

“…Interestingly from solvent screening studies, dimethyl carbonate was found to be the best alternative for dichloromethane and the most of the solvents were compatible solvents for the reaction except polar solvents such as water, DMSO, DMF and MeOH (entries 5-20). Further, elevating the reaction temperature increased the reaction rate with complete conversion (entries [18][19][20]. The FeCl 3 catalyst furnished a complete and clean conversion within 6 h at 90 C in dimethyl carbonate (99%, entry 20) and no traces of aldimine intermediate 3a were found in the reaction mixture.…”

“…In the case of aldehyde substrate containing a hydroxy group, under the optimized reaction conditions, the methoxycarbonylated product 4ad 0 was obtained in 96% yield instead of the expected product 4ad. 18 To overcome this particular substrate issue, switching solvent system to propylene carbonate afforded the desired product 4ad in 94% yield. Next, we examined the scope of aldehydes with 2-methyl-1,1-diphenylhomoallylamine (2b).…”